Animals can move from place to place, but plants cannot. When an animal is under attack, it can run away or fight back. Plants certainly cannot run away, and they lack teeth and claws. But plants can defend themselves by using both physical and chemical means.
Some plants have their own ways to keep animals away. For example, the leaves of the holly plant have sharp spines (刺) that discourage grass-eating animals. Holly leaves on lower branches have more spines than leaves on upper branches. This is because the lower leaves are easier for most animals to reach.
Some plants, such as the oak tree, have thick and hard leaves that are difficult for animals to eat. Some grasses may contain a sandy material; eating such grasses wears down the animal’s teeth.
Many plants also have chemical defenses. Some plants produce chemicals that taste bitter or cause an unpleasant reaction. Some plants may fight against an attack by increasing the production of these chemicals. When a caterpillar (毛虫) bites a tobacco leaf, the leaf produces a chemical messenger. This messenger sends to the roots the information to produce more nicotine. The higher levels of nicotine discourage the caterpillar.
Many plants depend on both physical and chemical defenses. A certain plant in China, for instance, has prickly (多刺的) leaves, and each prickle contains poisonous venom (毒液). A single experience with this kind of plant will teach an animal to stay away from it in the future.
67．The holly plant has more spines on the lower leaves because most animals________.
A．are not tall enough                                      
B．like the lower leaves only
C．are not clever enough                                   
D．can get the lower leaves easily
68．To defend themselves, oak trees use________.
A．chemical means                                             B．physical means
C．bitter chemicals                                             D．sandy materials
69．How does tobacco protect itself against an attack from a caterpillar?
A．Its leaves fight against the attack by physical means.
B．Its roots send a messenger to discourage the caterpillar.
C．Its roots increase the production of nicotine when it is attacked.
D．Its leaves produce poisonous sand to drive the caterpillar away.
70．What would be the best title for this passage?
A．Plants and Animals                                        
B．How Plants Defend Themselves
C．Attacks and Defenses                                   
D．How Animals Eat Plant Leaves

Even plant can run a fever, especially when they’re under attack by insects or disease. But unlike human, plants can have their temperature taken from 3,000 feet away straight up. A decade ago, adopting the infrared （红外线）scanning technology developed for military purposes and other satellites, physicist Stephen Paley came up with a quick way to take the temperature of crops to determine which ones are under stress. The goal was to let farmers precisely target pesticide (杀虫剂)spraying rather than rain poison on a whole field, which invariably includes plants that don’t have pest(害虫)problems.

Even better, Paley’s Remote Scanning Services Company could detect crop problems before they became visible to the eye. Mounted on a plane flown at 3,000 feet at night, an infrared scanner measured the heat sent out by crops. The data were transformed into a color-coded map showing where plants were running “fevers”. Farmers could then spot-spray, using 50 to 70 percent less pesticide that they otherwise would.

The bad news is that Paley’s company closed down in 1984, after only three years. Farmers resisted the new technology and long-term backers were hard to find. But with the renewed concern about pesticides on produce, and refinements（改进）ininfrared scanning, Paley hopes to get back into operation. Agriculture experts have no doubt the technology works. “This technique can be used on 75 percent of agricultural land in the United States,” says George Oerther of Texas A& M, who recently retired from the Department of Agriculture, thinks remote infrared crop scanning could be adopted by the end of the decade. But only if Paley finds the financial backing which he failed to obtain 10 years ago.

1.In what situation will plants have a fever?(No more than 8 words)(2marks)

2.How can we apply pesticide spraying precisely?(No more than 10 words)(2 marks)

3.Why may infrared scanning technology by brought back into operation?(No more than 13 words)(3 marks)

4.What is the biggest problem that might prevent bringing infrared scanning technology back?(No more than 7 words)(3 marks)

Plants can’t communicate by moving or making sounds, as most animals do. Instead, plants produce volatile compounds (挥发性化合物) —— chemicals that easily change from a liquid to a gas. A flower’s sweet smell, for example, comes from such volatile compounds to attract insects such as bugs and bees.
Plants can also discover  volatile compounds produced by other plants. A tree under attack by hungry insets, for instance, may give off these chemicals in order to let other trees know about the attack. In response, the other trees may send off their chemicals to keep the bugs away —— or even chemicals that will attract the bugs’ natural enemies.
Now scientists have created a quick way to understand what plants are saying: a chemical sensor (传感器) called an “electronic nose”. The “e-nose” can tell such compounds as plants make. When plants are attacked, scientists say, the e-nose could help quickly decide whether plants are being eaten by insects. But today, the only way to spot such insects is to inspect individual plants by observing them. This is a challenging task for managers of greenhouses, including those that can house thousands of plants. The research team is working with an e-nose that can recognize volatile compounds. Inside the device, 13 sensors chemically react with volatile compounds based on the interactions (相互作用), and then the e-nose will give off electronic signals that the scientists can analyze by using computer software.
To test the e-nose, the team presented it with healthy leaves from cucumber, pepper and tomato plants, all being common greenhouse crops. Then scientists collected samples of the air around damaged leaves from each type of crop. These plants had been damaged either by insects or by scientists who made holes in the leaves with a hole punch (打孔器).
The e-nose, it turns out, can identify healthy cucumber, pepper and tomato plants based on the volatile compounds they produce. It could also identify tomato leaves that had been damaged. But even more impressive, the device could tell which type of damage —— by insects or with a hole punch —— had been done to the tomato leaves.
With some fine-tuning (微调), a device like the e-nose can one day be used in greenhouses to quickly spot harmful bugs, the researchers say. A device like this can also be used to identify fruits that are perfectly ripe and ready to pick and eat, says Natalia Dudareva, a biochemist at Purdue University in West Lafayette, India, who studies smells of flowers and plants. Hopefully, scientists believe, the device can bring large benefits to greenhouse managers in the near future.
【小题1】We learn from the text that plants communicate with each other by ______.

The fire fighters soon got the fire in the building        

    A．under attack       B．under control

    C．under construction   D．under way

Two Christmas traditions have come under attack in recent years from environmentalists: Christmas cards and Christmas trees.
Paper cards are seen as wasteful and, for some people, going card-free is another way of going green. They also argue that in a world of e-mail, Skype, Facebook and Twitter, people are in touch all the time anyway; they no longer need the yearly card that connects them with long lost friends. If you want to send Christmas greetings, there are free e-cards, which get the job done with no postage or wasted paper.
However, especially for people who didn’t grow up with e-mail, there is something missing from a Christmas e-mail. The first Christmas cards appeared in London in 1843 and were designed by the same man who had introduced the world’s first postage stamp three years earlier. His name was Sir Henry Cole.
They rose in popularity throughout the 20th century. Many people sent cards that were sold for charity. The most famous of these are the ones sold for UNICEF. In the UK this year, in the three weeks before Christmas, the post office expects to handle 100 million cards every day. Environmental awareness also means that nowadays many people recycle their cards; this helps raise money to plant more trees, as well as recreating more paper.
When we think of trees at Christmas, there is one that immediately springs(跃入)mind---the evergreen tree that people decorate with ornaments and place their presents under. The custom dates back almost a thousand years to Germany. Nowadays 33 to 36 million Christmas trees are produced in America and 50 to 60 million in Europe each year. Some trees are sold live with roots and soil so people can plant them later and reuse them next year.
Some people prefer artificial trees as they are reusable and much cheaper than their natural alternative. However, environmentalists point out that they are made from petroleum (石油) products and so have many pollution issues.
【小题1】What is the main idea of the article?